Many people use mobile nodes, such as cell phones and personal digital assistants (PDAs), to communicate with wireless communication networks. These mobile nodes and networks typically communicate over a radio-frequency (RF) air interface according to a wireless protocol such as Code Division Multiple Access (CDMA), perhaps in conformance with one or more industry specifications such as IS-95, IS-856, and IS-2000. Other protocols may be used as well, such as iDEN, TDMA, AMPS, GSM, GPRS, UMTS, EDGE, WiMAX (e.g., IEEE 802.16), LTE, microwave, satellite, MMDS, Wi-Fi (e.g., IEEE 802.11), and others now known or later developed.
In a wireless communication network operating according to the well known IS-856 (e.g., 1xEV-DO) standard, data transmissions occur from the wireless communication network to one or more mobile nodes. The data transmissions occur on a time-division-multiplexed basis, in which the wireless communication network typically communicates with a single mobile node in a given time slot. The data transmissions from the wireless communication network to a given mobile node are said to occur on a forward link, while those from a given mobile node to the wireless communication network are said to occur on a reverse link.
Under IS-856, mobile nodes assess air-interface conditions and then use these assessments to request particular data rates by sending what is known as data rate control (DRC) information to the wireless communication network. In particular, each mobile node monitors the signal-to-noise ratios of signals it receives from various sectors of the wireless communication network and selects a serving sector that has the best (highest) detected signal-to-noise ratio. Applying a simple correlation table, the mobile node then determines a “DRC value” that corresponds with the measured signal-to-noise ratio, and the mobile node sends to the wireless communication network a DRC message specifying the determined DRC value for forward-link communication. The network then correlates the provided DRC value to a data rate at which the network should transmit data to the mobile node. When the mobile node later requests data communication from the network, the network transmits data to the mobile node on the forward link at the requested data rate, if possible.
Wireless communication networks—including EV-DO networks—typically include a plurality of base stations, each of which provides one or more wireless coverage areas. A wireless coverage area of a base station has a respective radiation pattern that defines one or more sectors. A mobile node positioned in one of these wireless coverage areas can communicate over the air interface or “RF-link” with the base station, which may provide the mobile node access to one or more circuit-switched, packet-switched, and/or other transport networks. Mobile nodes and base stations conduct RF-link communication sessions (e.g. voice calls and data sessions) over frequencies known as carrier frequencies. Using a sector as an example of a coverage area, base stations may provide service in a given sector on one or more carrier frequencies.
A wireless service provider may manage a wireless communication network to provide sufficient bandwidth for requested data-communication sessions in the wireless communication network. If insufficient bandwidth is available to serve all requests for data-communication sessions in one or more sectors of the wireless communication network, the wireless service provider may add capacity to the wireless communication network, such as by adding one or more carrier frequencies to each of one or more sectors having insufficient bandwidth (i.e., capacity). However, adding capacity to a wireless communication network often requires a significant expenditure of capital and time.